OK, So I have been doing all the reading and have done everything I could trying to avoid this.

I have a 1999 7.3 PSD, The truck idles rough, Stalls at Idle and low speed/RPM's, Surges, Hesitates on take off.

This is what I have done so far:

Swapped IDM's, Swapped IDM Relay, New CPS, Removed Bully Dog 4-Bank, and Checked the Injector wiring on the outside of the valve covers, and I still have the same problem.


This was done at operating temp, in park and holding around 2000 RPM's

Engine Speed 2011 RPM
AP Sensor (V) 0.92V
BARO (P) 14.2V
CONT DTC's 2
EXH Back (P) 53.3 psiA
EXH Back PR Reg 0%
FUEL Inj PW 1.62ms
Glow Plug DC 0%
GP Control 0.0s
GP Lamp 0.0s
MAP (P) 15.1psi
Manifold (P) 0.9 psiG
Net Engine Torqu 28 lb-ft
VREF Voltage 5.00mV
EOT 136F
EOT (V) 1.46V
Exhaust BP (V) 4.78V
BARO (V) 4.44V
EXHAUST BP 366.4 psiG
VPWR Voltage 14.0V
MAP (F) 0.0Hz

A Mastertech Scanner was used. The Exhaust is 4" and Open and possibly has a 5" Resonator. The 2 DTC's are:

P0470 Ex Back Press Sensor CKT MALF
P0478 Ex Back Press Control Hi Input

Any Help would be greatly appriciated. Thanks

Ryan

Also just checked the tube coming from the exhaust manifold to the sensor on the front of the engine behind the idler pulley.

 

Any Help would be greatly appriciated. Thanks

Ryan

Also just checked the tube coming from the exhaust manifold to the sensor on the front of the engine behind the idler pulley.


did you run a wire though the tube and clean the bottum of the sencor it went to (EBPS)

 

Those backpressure numbers are way to high just reving

Did you ohm the injectors through the harness?

 

No I didnt Ohm the injectors, but I did a buzz test and all injectors sounded to be equal. What should backpressure be at 2000 RPM's?

Ron, No I didnt run a wire thru the tube, I just disconnected it from the EBPS and felt the exhaust coming from it.

Thanks for all the help so far.

Ryan

 

its the tube or the sencor that will plug up..but i would fallow amiller on this one..he is prety good at this

 

Driving down the raod under load backpressure normally sits in the 30's or 40's depending on exhaust mods.
At WOT in park/neutral it should not excede 28psi.

With what you are descibing it sounds like the wiring under the valve covers
Check here https://www.ford-trucks.com/forums/2...or-wiring.html

 

Amiller93, Would this give me the high backpressure also, or could it be a combination of both UVC wiring and EBPS?

 

That tube tends to get clogged with soot and will usually show low backpressure. with a high back pressure it is usually either the sensor is bad or an exhaust restriction (EBP valve stuck shut, dented exhaust pipe, clogged muffler, ect.)

PM me your email address and i can send you the pinpoint test for the sensor.

 

amiller93, I couldnt send you a PM with my email cause I dont have 50 posts and havent been a member for 15 days. I seen you are a firefighter, me too. My email is

 

Email on the way

BTW edit your post and remove your email address so an attacking bot cant scavenge it.

 

Thanks amiller, It looks like I will be having a busy day on Friday. I know the UVC wiring harness is cheap and the local IH dealer has them in stock, I may just go ahead and replace both sides and maybe the EBPS too.
Is it common for there to be alot of soot around the turbo? I just noticed it while I was looking for the Exh Back pressure valve. Is there any way to tell if it is stuck shut?

 

If you can run a KOER test with that scanner it will activate it and you can watch it move. If you have alot of soot behind the turbo check the uppipe donuts for leaks.

 

What is the KOER test? I ran every test that scanner would run and dont remember seeing that?

 

Key on Engine Running.

If ambient temp is below 45* and engine oil temp is below 131* once you crank it the PCM will command the EBP valve to shut to speed the warm up about 20 -30 seconds after starting.